crude oils and fuels

Question 1

what is crude oil a mixture of

Answer 1

hydrocarbons

compounds that only contain hydrogen and carbon - joined together by covalent bonds

most are alkanes

Question 2

what is the general formulae for the family of alkane hydrocarbons

Answer 2

C(n)H(2n+2)

eg methane = CH(4)
ethane = C(2)H(6)

Question 3

draw methane as an alkane molecule displayed formulae

Answer 3

H
        |
H--C--H
        |
       H

covalent bonds =straight line
atom is shown as its symbol

Question 4

name the alkanes in order of smallest to biggest

Answer 4

methane
ethane
propane
butane
pentane 
hexane
octane
montane
decade

Question 5

what type of hydrocarbons are alkanes

Answer 5

saturated hydrocarbons

means contain as many hydrogen atoms as possible in each molecule

no more hydrogen atoms can be added

Question 6

what’s a saturated hydrocarbon

Answer 6

carbon atoms are joined together by single bonds

makes them unreactive
apart from boring or combustion which is their reaction with oxygen in the air

Question 7

what is distillation

Answer 7

process used to separate pure liquid from a mixture of liquids

works when liquids have different boiling points

heats(evaporates)> cools (condenses)

Question 8

how is fractional distilation different to normal distillation

Answer 8

different from distilation cause it separates mixture into different parts called fractions

Question 9

how does fractional distillation work

Answer 9

1. crude oil is heated to evaporate
2. crude oil fed at bottom of a tall Column as hot vapour
3. hot at bottom cool at top, several condensers coming off at different heights
4. gases condense when they reach their boiling points
5. different fractions are collected as different liquids at different levels

boils/condenses at different temperatures cause of different sizes of molecules

Question 10

what has the lowest boiling points

Answer 10

Petrol , refinery gas (shorter carbon atoms)

Question 11

what has the highest boiling points

Answer 11

bitumen, oil (longer carbon atoms)

cool to form very thick liquids or solids at room temperature

Question 12

what are properties of short chain alkanes

Answer 12

low boiling point

less viscous( more runny)

more volatile(more likely to turn into a gas)

more flammable (easier it burns)

Question 13

what are the properties of long chain alkanes

Answer 13

high boiling point

more viscous( less runny)

less volatile(less likely to turn into a gas)

less flammable (harder it burns)

Question 14

where is crude oil derived from

Answer 14

biomass found in rocks, over millions of years

Question 15

what comes out of the bottoms of fractional distillation Collums

Answer 15

residue

very thick, mixture of long-chain hydrocarbons, used in making roads and flat roof

Question 16

what happens when the fractions have been collected

Answer 16

they need more processing before they can be used

Question 17

are the long chain atoms near the bottom of the top in fractional distillation

Answer 17

substances with higher boiling points (long chain) condense at bottom and lower boiling points (short chain) condense at least he top

each fraction contains hydrocarbon molecules with a similar number of carbon atoms

Question 18

what are lighter fractions used for and why?

Answer 18

used a fuels

because when they burn in plenty of air they release energy

called oxidised (meaning adding oxygen in a chemical reaction in which the oxides are formed)

propane+ oxygen > carbon dioxide+ water

Question 19

how can we test that carbon Dixie is produced in combustion

Answer 19

limewater goes cloudy

Question 20

how can you tell that water is produced in combustion

Answer 20

blue colbalt paper goes from blue to pink

Question 21

how is selfie dioxide produced

Answer 21

impurities containing sulphur is a product of fuels being burnt as fuels.

sulphur reacts with oxygen when we burn the fuel- creating sulphur dioxide

Question 22

what is sulphur dioxide and what does it do

Answer 22

poisonous gas

acidic

causes acid rain

can cause engine corrosion

Question 23

what is incomplete combustion and when does it happen

Answer 23

when there isn’t enough oxygen

instead of carbon dioxide being produced carbon monoxide is produced

Question 24

why is carbon monoxide poisonous

Answer 24

red blood cells pick it up and carry it around the blood instead of oxygen

even small amounts of carbon monoxide can be bad for you

Question 25

how are nitrogen oxides formed

Answer 25

high temperatures in an engine allow nitrogen and oxygen to form nitrogen oxides.

Question 26

what is nitrogen oxide

Answer 26

poisonous can trigger asthma attacks cause acidic rain

Question 27

what is particulates

Answer 27

tiny solid particles containing carbon and Unburnt hydrocarbons get carried into the air scientists think they damage our lungs and might cause cancer

Question 28

how are particulates produced

Answer 28

in Diesel engines hydrocarbons are burnt with much bigger molecules big molecules react with oxygen and don't always burn completely - particulates are produced

Question 29

what does carbon dioxide do

Answer 29

main greenhouse gas in the air absorbs energy released as radiation from surface of the earth causes global warming, increased world's temperature.

Question 30

what do particulates do

Answer 30

tiny solid particles made from carbon and Unburnt hydrocarbons travel into the upper atmosphere, reflecting sunlight back into space- causing global dimming

Question 31

what does carbon monoxide do

Answer 31

affects the amount of oxygen that our blood is able to carry particularly serious for people who have heart problems

Question 32

what does sulfur and nitrogen oxides do

Answer 32

make people suffer from asthma because of increased air pollution cause acid rain because they dissolve in water droplets in the atmosphere and react with oxygen creating sulphuric and nitric acids rain with a low oh can damage plants and animals

Question 33

what's a catalytic converter

Answer 33

catalytic converters in car exhausts- reduces carbon monoxide and nitrogen oxides produced expensive because they contain precious metal catalysts- but are very effective do not help reduce levels of carbon dioxide

Question 34

how do catalytic converters work

Answer 34

metal catalysts arranged so they have a large surface area causes carbon monoxide and nitrogen oxides to react together and produce nitrogen and carbon dioxide carbon monoxide + nitrogen oxide> carbon dioxide + nitrogen

Question 35

what do filters do

Answer 35

remove most particulates from the modern diesel engines. the filets need to burn off trapped solid particulates otherwise they will get blocked

Question 36

how is sulfur dioxide removed in power stations

Answer 36

removed from flue (waste) gases by reacting it with calcium oxide or calcium hydroxide. sulfur é impurities can also be removed from fuel before the fuel is burned (happens in cars and factories)

Question 37

so have can you reduce the effects of burning fuel

Answer 37

1. catalyst converters 2. filters 3. reacting sulphur with calcium oxide/calcium hydroxide 4. removing sulphur from fuel before burning fuel

Question 38

what's a biofuel

Answer 38

fuels made from plant or animal products

Question 39

what's a biodiesel

Answer 39

fuel for cars made from plant oils

Question 40

what are the advantages of biodiesel a

Answer 40

1. cheaper than petrol and diesel - crude oil price going up 2. carbon neutral 3. it's renewable and reliable 4. makes other useful producers eh high energy food for goes and soap

Question 41

what does carbon neutral mean

Answer 41

the amount of carbon dioxide given off when it burns is balanced by the amount absorbed as plants it is made from grow

Question 42

What are the disadvantages of biodiesels

Answer 42

1. freezes before traditional diesels and can turn into sticky goo at high temperatures in a engine 2. can destroy habitats- large areas of tropic forest are being cut down and turned into Palm oil plantations for biodiesel- orangutans habitats destroyed 3. used late areas of farmland where food could be produces. food becomes too expensive in poorer countries and people die

Question 43

what happens in complete combustion with hydrocarbons

Answer 43

the carbon in the hydrocarbons oxidises to carbon dioxide the hydrogen oxidises to water but needs to be plenty of air!!

Question 44

what is exothermic

Answer 44

a type of energy that releases energy from a fuel